This chapter describes an empirically based model of how the brain causes behavior and how different brain areas interact to initiate and control movement. In particular, it looks at the role of the frontal cortex/basal ganglia loops in initiating interaction between intention and motivation. After providing a brief overview of the structure and function of the motor system in the human brain, the chapter considers the concepts of “willed intentions” and “sensorimotor intentions” and discusses Benjamin Libet’s experiments on the timing of consciousness in relation to voluntary movement.